J.B.
I still feel guilty sometimes when my youngest "mama's boy" cries as I drop him off at preschool. However, I felt guiltier when we couldn't afford to buy them anything, take them the places I wanted to take them and have experiences with them we wanted to have. I also felt guilty being on edge, screaming and being unhappy because I DO NOT enjoy staying at home all the time! We have a lot more quality time now! I have to say, my oldest is in kindergarten, but both he and my youngest have learned so much and blossomed so much in preschool and in pre-k -it's been great for them. And quite honestly, even though I still feel bad once in awhile, it's been really great for me too!
Also, have you left them at daycare or preschool before with them screaming? My youngest ALWAYS does this -it's almost a game with him -but my oldest never has. I was prepared for it, but he was always excited to go. So, it may not be the nightmare you're imagining